A Low-Cost 1 Mbps Frequency Shift Keying Backscatter Receiver and Carrier Wave Generator System for Wireless Neural Recording

摘要

We present a low-cost, highly configurable receiver and external CW generator for frequency shift keying (FSK) based backscatter communication systems. The receiver uses a Nordic Semiconductor nRF24L01+ chip and an Arduino UNO to enable backscatter communication on any of 125 channels within the 2.4 GHz industrial, scientific, and medical (ISM) band. The receiver supports FSK modulation at up to 2.0 Mbps. Paired with an Arduino-based carrier generator, this system allows users to choose a backscatter uplink channel that minimizes interference from other 2.4 GHz devices (e.g. Wi-Fi and Bluetooth). As an example of a power-critical sensing application where backscatter can be used favorably, we present a wireless, digital neural recording system that leverages a 1.0 Mbps FSK backscatter uplink. The neural recording system has a 3 dB frequency response of 0.8 Hz to 220 Hz and uplinks up to 120 kbps of biopotential data at a sample rate of 500 Hz, with 16 bits of precision per sample. The packet uplink rate is 500 packets per second.